anyone know whether the ImagesCollide code is optimised to first check the coords of the two images before possibly wasting time testing them?
Don't know for a fact, but I've heard that it does. Also does anyone know if it is worth making a black and white image (1 bit depth) of your graphics to pass into ImagesCollide or does it do this automatically?
Not necessary. ImagesCollide uses the mask color to determine 'empty' pixels. The mask color is black by default. If you need it to be a different color, then use the MaskImage command to change it. Finally is there a quick and easy way of converting a 24 bit image two 1 bit depth in code
Unnecessary, due to previous response.